Computer System, License Management Method and Program

1. A computer system that manages licenses of an application, comprising: a communication device; and one or more processors that: acquire a number of owned licenses from each of a plurality of providing sources via the communication device; calculate a number of unused licenses which are not currently used among the acquired number of licenses; determine a number of rentable licenses from the calculated number of unused licenses; acquire a number of required licenses via the communication device; determine whether the number of required licenses satisfies the number of rentable licenses in one providing source; extract rentable licenses from fewest providing sources among the plurality of providing sources when the number of required licenses does not satisfy the number of rentable licenses in one providing source; and provide the extracted rentable licenses.

2. The computer system according to claim 1 , further comprising a storage device that stores the number of rentable licenses and a rental period of the rentable licenses in association with each other, wherein the one or more processors provide the rentable licenses during the rental period.

3. The computer system according to claim 2 , wherein the one or more processors provide a minimum number of licenses among numbers of rentable licenses in the rental period.

4. The computer system according to claim 1 , wherein the one or more processors determine the fewest providing sources among the plurality of providing sources when the number of required licenses does not satisfy the number of rentable licenses in one providing source, a total number of rentable licenses in the fewest providing sources being greater than or equal to the number of required licenses.

5. A license management method of managing licenses of an application, the method comprising: acquiring a number of owned licenses from each of a plurality of providing sources; calculating a number of unused licenses which are not currently used among the acquired number of licenses; determining a number of rentable licenses from the calculated number of unused licenses; acquiring a number of required licenses; determining whether the number of required licenses satisfies the number of rentable licenses in one providing source; extracting rentable licenses from fewest providing sources among the plurality of providing sources when the number of required licenses does not satisfy the number of rentable licenses in one providing source; and providing the extracted rentable licenses.

6. The method according to claim 5 , wherein extracting the rentable licenses includes determining the fewest providing sources among the plurality of providing sources when the number of required licenses does not satisfy the number of rentable licenses in one providing source, a total number of rentable licenses in the fewest providing sources being greater than or equal to the number of required licenses.

7. A non-transitory computer-readable medium that stores a program for causing a computer system that manages licenses of an application to execute: acquiring a number of owned licenses from each of a plurality of providing sources; calculating a number of unused licenses which are not currently used among the acquired number of licenses; determining a number of rentable licenses from the calculated number of unused licenses; acquiring a number of required licenses; determining whether the number of required licenses satisfies the number of rentable licenses in one providing source; extracting rentable licenses from fewest providing sources among the plurality of providing sources when the number of required licenses does not satisfy the number of rentable licenses in one providing source; and providing the extracted rentable licenses.

8. The non-transitory computer-readable medium according to claim 7 , wherein extracting the rentable licenses includes determining the fewest providing sources among the plurality of providing sources when the number of required licenses does not satisfy the number of rentable licenses in one providing source, a total number of rentable licenses in the fewest providing sources being greater than or equal to the number of required licenses.